The use of catheters, wire guides, pacemaker leads, and other medical devices in the vascular system of a patient often results in the breakage or fragmentation of the device. Once broken or fragmented, a fragment of the device is released in the vascular system of a patient. Even simple, routine procedures such as intravenous infusion and pressure monitoring can result in a fragment or foreign body being released in the bloodstream of a patient. This foreign body typically moves through the bloodstream and potentially causing a number of clinical complications including sepsis, perforation, thrombosis, arrhythmias, myocardial necrosis, and death. Therefore, it is necessary and urgent to remove the foreign body from the vascular system of a patient.
One approach to removing a foreign body from the vascular system of a patient is to perform open surgery, which is costly, traumatic, requires long periods of healing and recovery, and implies a further risk of complications. If the foreign body is positioned in a branch of a pulmonary artery, for example, a thoracotomy procedure is required. As a result, a patient who has only undergone a routine vascular access procedure for testing or diagnosis can be required to undergo major surgery due to a complication.
Another approach to removing a foreign body from the vascular system of a patient is the use of a retrieval device during a minimally invasive vascular access procedure typically performed with a visualization aid such as fluoroscopy. Several retrieval devices are proposed for this use. One proposed retrieval device has a distal hook. The distal hook is positioned centrally along the length of an elongated fragment or foreign body for grasping the fragment. Then the retrieval device is pulled so that the fragment is dragged through the vascular system and out of the patient's body. A limitation of this device is that the hook cannot grasp and pull a very short fragment or foreign body. A problem with this device is that it grasps the fragment in a transverse orientation with respect to the axis of the retrieval device. As a result, the fragment extends from the hook at an angle, which makes manipulation through the tortuous vessels of the vascular system problematic. The transversely extending fragment potentially traumatizes and catches on blood vessel walls. Another problem with the use of this device is that the elongated fragment trails the hook in a doubled strand during travel through the tortuous vascular system. As a result, the fragment causes significant drag or friction so that the fragment slides out of the hook and, again, traumatizes blood vessel walls.
Another retrieval device has a distal loop or snare for being positioned over one end of an elongated fragment and tightened thereabout. A problem with this device is that it grasps an elongated fragment transversely with respect to the axis of the retrieval device. Again, the transversely extending foreign body potentially traumatizes blood vessel walls during travel through the vascular system of the patient. Furthermore, the foreign body can become caught or wedged in the tortuous vessels and require surgical removal. Another problem with a distal loop is that the loop wire can be easily kinked during engagement of the fragment. As a result, the snare is often rendered ineffective and should be replaced.
Another retrieval device has a pair of distally positioned forceps jaws for grasping a foreign body anywhere along the length thereof. A problem with this device is that the narrow, tortuous vessels of the vascular system offer limited space for the forceps jaws to open and close. Another problem with this device is that the jaws are typically used to grasp the central portion of an elongated fragment. As a result, the fragment has a transverse orientation with respect to the axis of the retrieval device. Again, the problems of traumatizing vessel walls and inadvertently releasing the fragment from the retrieval device are presented.